Crankcase lubricant



Pat'entcd Feb. 19, 1946' 2,395,105 CRANKCASE LUBRICANT Elmer W. Cook, New York, N. Y., and William D.

' Thomas, Jr., Stamford, Comm, assignors to American Cyanamid Company New York, N. Y., a corporation of Maine 1 No Drawing. Application September 10, 1943, Serial No. 501,848

2 Claims. (Cl. 252-33) This invention relates to addition agents for lubricating oils of the type known as crankcase oils; 1. e., hydrocarbon oils of the types which are used in the crankcases of internal combustion engines. It is a principal object of the inventionto provide a novel class of crankcase oil additives which are readily oil-soluble and will function as anti-oxidants and corrosion inhibitors in the oil. A further object resides in the provision of a class of oil-soluble metal salts of these compounds which possess the above properties and arealso detergents and sludge-dispersing agents.

- amide is produced.- The phenol sulfonamide may We have discovered that certain arylsulfonamides of the type hereinafter defined possess the requisite solubility and heat-stability to function as additives for lubricating oils despite the fact that they are nitrogen-containing compounds. This discovery has enabled us to employ the higher aliphatic primary and secondary amines such as octylamine, dioctylamine, monoand didecylamine, dodecyl amine and octadecyl amine in the preparation of additives for lubricating oils. Since the aliphatic amines are relatively cheap compounds containing long aliphatic chains that promote oil-solubility, our discovery represents an important improvement in the ar The arylsulfonamides which we have found to possess anti-oxidant and corrosion-inhibiting properties in lubricating oils are prepared from alkyl-substituted phenols which contain at. least 8 and preferably 10 or more carbon atoms in the side chain or chains thereof and alkyl amines in which the aliphatic radical is at least 8 carbon atoms in length. The sulfonamides prepared by the use of these two classes of raw materials are both oil-soluble and heat-stable, and may be used in the form of the free phenols or their alkali metal salts in amounts of 0.1-5% or more, based on the weight of the oil. However, we prefer to employ these products in the form of their metal salts, such as the calcium, barium, zinc and aluminum salts, since this form they possess good detergent and sludge dis'persing properties in addition to their anti-oxidant and anti-corrosion properties. Our invention in its broader aspects therefore includes the phenolic arylsulfonamides in the form of their alkaline earth, aluminum and heavy metal salts of these phenolic compounds which constitute the preferred embodiments thereof.

Our new additives are preferably prepared by reacting a phenol sulfonate in which the .phenolic group contains one or more alkyl substituents containing a total oft or more carbon atoms with then be transformed into a metal salt by reaction with metal oxides-or hydroxidessuch as barium, calcium and strontium hydroxides, or the zinc, aluminum or other metal salts may be prepared by double decomposition between a sodium salt of the sulfonamide and an anhydrous chloride of the metal in'alcoholic solution. The resulting metal salts are readily soluble to 50% solutions in lubricating oils of the types used in the crankcases of internal combustion engines, and these stock solutions may be blended with further quantitles of lubricating oils to produce solutions containing 0.1-5% of the metal salt, based on the weight of the oil, which are the optimum concentrations for use.

A wide variety of alkyl-substituted phenols and phenol sulfonic acids in which the substituent groups contain a total of at least 8 carbon atoms is available for preparing the sulfonamides used in practicing the present invention. In addition to such monoalkyl phenols as 4 octyl and 4-dodecyl phenols and such dialkylphenols as 2,4-dibutyl and diamyl phenols, 2-butyl-4-octyl phenol and the like, the alkylphenols formed by the condensation of phenol and cresols with aliphatic hydrocarbons may be used. Thus, for example, kerosene, hydrocarbon Waxes and other aliphatic hydroc'arbons of 8-22 or more carbon atoms may be chlorinated and then condensed with phenol or cresol in the presence of zinc chloride or aluminum chloride catalysts. Lower unsaturated hydrocarbons such as propylene, butylene and the like can also be condensed with phenols or cresols to produce alkylated phenols containing the requisite oil-solubility. A monosulfonate of the condensation product of phenol with chlorinated kerosene is now available on the market under the trade-name Nacconal NR and may be employed in preparing the additives of the present invention.

Any of the phenols described above may be sulfonated by any suitable means, such as by the use of sulfuric acid monohydrate or oleum, but we prefer to employ sodium chlorsulfonate as the sulfonating medium. The resulting sulfonic acids are transformed into the corresponding sulfon chlorides by heating a solution of their alkali metal salts in anorganic solvent such as petroleum naphtha with an excess of phosphorous trichloride. We have found that the sulfon chlorides obtained in this manner will condense readily with aliphatic primary amines containing 18 or more carbon atoms by agitating the mixture at about 50-80 C. for 30-60 minutes or slightly longer. The resulting condensation products are both oil-soluble and heat-stable, and possess good antioxidant properties for the prevention of bearing corrosion in internal combustion engines.

As has been stated, the sulfonamides of the invention are preferably used in crankcase oils in amounts of about 0.1-5%, depending on the conditions of service, although they may be prepared as stock solutions of much higher concentration for purposes of shipping and storage. They may also be used in conjunction with other lubricating oil additives of any desired type; thus, for example, the addition 2,4-dibutyl, diamyl or other dialkylphenol monosulfides or the calcium, barium, aluminum or other heavy metal salts thereof in amounts approximately equal to the amount of alkarylsulionamide in the oil will give improved protection against sludge formation upon continued exposure to high temperatures. Similarly such antioxidants and detergents as the heavy metal salts of the dialkyl, diaryl or mixed alkylaryl esters of phosphoric acid, thiophosphoric acid, dithiophosphoric acid and the like may be added in about the same quantities.

The invention will be illustrated in greater detail by the following specific examples. It should be understood, however, that although these examples may describe in detail some of the more specific features of the invention, they are given primarily for purposes of illustration and the invention in its broader aspects is not limited thereto.

Example 1 100 parts by weight of 2.4-diamylphenol and 68 parts of sodium chlorsulfonate were dissolved in about 200 parts of dioxane and reacted by heating at 50-60 C. for 45-60 minutes. The solution was then filtered and the solvent evaporated irom the filtrate.

The resulting 2,4-diamylphenol sodium sulfonate was dissolved in solvent naphtha and 29.4 parts by weight of phosphorus trichloride were added. The mixture was then refluxed for about 30 minutes to convert the sulfonate to 2,4-diamylphenol sulfonyl chloride after which it was filtered to remove the phosphorus compounds. 80 parts of laurylamine were then added and the mixture was agitated at 50-60 C.for about 30 minutes, or until the condensation was complete. After washing with dilute ammonium hydroxide and evaporating the solvent, the 2,4- diamylphenol sulfon lauryl amide was obtained as a brown, viscous material, soluble in lubricating oil.

Example 2 96 parts by weight of the product of Example 1 were dissolved in 55 parts of petroleum naphtha and 55 parts of ethyl alcohol and 35 parts of Ba(OH)2.8H2O were stirred in, this being a excess over the amount necessary to form a salt It was the barium salt of z A-diamylphenol sulfon lauryl amide of the formula A Mid-Continent, solvent-refined lubricating oil containin 0.5% by weight of the above compound was tested in comparison with another sample of the same 011 containing no additive by the Catalytic Indiana test.

The apparatus for this test consists of a constant temperature bath maintained at 341 F. in which a number of large glass tubes are immersed. 300 cc. samples of the oil. under test are poured into these tubes and air at the rate of 10 liters per hour is bubbled through the oil. In order to reproduce the conditions existing in the crankcase of an engine weighed strips of copper-lead alloy are suspended in the 011 samples. As metallic surfaces, particularly copper, greatly accelerate the rate of oxidation and decomposition of the oil in the presence of oxygen this is an important factor in the test. Bearing corrosion rates are determined by again weighing the strips after '70 hours immersion, which is the test period normally used.

The bearing strip in the oil containing no additive lost 328 milligrams, while there was no corrosion loss in the oil containing the additive. The sludge formed on the walls of the tubes was dispersing properties.

Example 3 48 parts by weight of the product of Example 1 were dissolved in ethyl alcohol containing 4: parts of NaOH and an alcoholic'solution containing 6.8 parts of anhydrous zinc chloride was added. The mixture was stirred until the salt formation was complete, filtered, and the alcohol removed by evaporation under, a vacuum. The resulting zinc salt of 2,4-diamylphenol sulfon lauryl amide was obtained as a dark brown, waxy solid and dissolved in lubricating oil to make a 50% solution. This solution was blended with further quantities of the same oil to produce a crankcase lubricant containing 0.6% of the additive, based on the weight of the oil.

- Example 4 the calcium and barium salts by dissolving in a mixture of toluene and ethanol, adding an excess of the metal hydroxide, heating to complete the salt formation and expel the water of reaction, filtering from unreacted solids, and evaporating thesolvent. All three of the salts were similar in appearance, being brown, waxy solids that were readily soluble in lubricating oil.

All of the products were subjected to the Catalytic Indiana test, using the same S. A. E. grade Midcontinent oil described in Example 2. The results after 70 hours are given in the following table:

From these results it is evident that both the free aryl sulfon alkyl amides and their metal salts are excellent anti-oxidants and corrosion inhibitors for lubricating oils. The metal salts are also detergents and sludge dispersing agents and will therefore protect the oil against the formation of hard lacquer deposits that cause stuck piston rings in the engine.

Example 5 A solution of 20.6 parts by weight 01 4-octylphenol and 15.4 parts of sodium chlorsuli'onate in 43 parts of dioxane was heated at about 60 C. for 1 hour, filtered, and the solvent evaporated from the filtrate. The product was dissolved in solvent naphtha and refluxed for 30 minutes with parts of PC13, filtered, and 2'? parts of laurylamine were added. The mixture was then heated with agitation at 60 C. for -40 minutes to form the 4-octyl-phenol sulfon stearyl amide which was isolated and transformed into its barium salt by the method described in Example 2. The product was easily soluble in lubricating oil to form a 50% solution. When tested by the method described in the preceding examples in amounts of 0.2-1%, based on the weightof the oil, it was found to be an eflective anti-oxidant and to possess good detergent properties.

Erample 6 105 parts by weight oi. "Nacconol NR were extracted with hot ethyl alcohol and the solvent was evaporated under reduced pressure. There remained 19.5 parts of residue which was principally sodium alkylphenol suli'onate. This material was heated on a steam bath with 25 parts by weight of phosphorous pentachloride for one hour, after which benzene was added and the mixture was The benzene and phosphorous oxychloride were removed by distillation under reduced pressure. leaving 19-20,parts of a dark colored oil. .To this oil was added 11 parts by weight of laurylamine and 4 of pyridine dissolved in octane. The resulting mixture was heated at 90 C. for two hours, filtered, evaporated to dryness and vacuum dried. Since the active material in Naccono1NR"is ob- 5 tained by condensing phenol with chlorinated kerosene the final product was keryP' phenol sulfon laurylamide, the keryl group being an aliphatic radical of approximately 12 carbon atoms.

parts by weight of the product were dissolved 10 in a mixture of petroleum naphtha and butanol.

and 7 parts of Ba(OH)z.8H20 were added. The

barium salt was then formed by continuedheating until all the water had been removed. The resulting mixture was filtered to remove unis reacted barium compound, 37 parts of S. A. E. 10

lubricating oil were added, and the low-boiling solvents were stripped ofl by heating at reduced pressures. The product was a solution of the barium salt of the alkylphenol sulfonlauramide 0 in lubricating oil.

What we claim is: 1. A crankcase lubricant comprising a lubricating oil having dissolved therein 0.l-5% of a metal salt of an arylsulfonamide having the 25 formula in which a: is an alkyl radical, Y is a member of 5 the group consisting of hydrogen and alkyl radicals and :c and Y together contain a total of at 0 '2. A crankcase lubricant comprising a lubrieating on having dissolved therein 0.1-5% 0! a divalent metal salt of an arylsulionamide having the formula Me 0 O i RLNELSO Y LNfi-R' :r r I in which a: is an alkyl radical, Y is a member or the group consisting of hydrogen and alkyl radicals and a: and Y together contain a total of at least 8 carbon atoms, R is an aliphatic radical of 8-18 carbon atoms and Me is an alkaline earth metal.

0 ELMER W. COOK.

WIILIAM D. THOMAS, JI. 

